In brass instruments, a valve mechanism (valve device) for scale adjustment is in practical use as an input/output part of a resonance tube because of its advantage of being capable of instantaneously bringing the resonance tube necessary for scale adjustment into communication via a piston hole irrespective of the length of the musical instrument and the order of a harmonic. Here “harmonics” refer to notes produced with the same fingering by controlling an aperture (size of an air column), a resistant feeling (pressure) of breath, and a change in tension (support) of muscles of sounding organ parts, which are factors controlling the pitch of a note in a brass instrument such as a trumpet. In other words, if “sol (G)” note is produced when the musical instrument is blown normally, the same “sol (G)” note which is one octave higher or two or more octave higher can be produced when the musical instrument is blown harder with the same fingering, and this high-pitch note is called a “harmonic”. For example, as in a three valve system (having three valves in serial communication) in which one resonance tube is coupled to a sidewall of each columnar hollow portion called a valve casing, an ordinary valve mechanism for brass instrument adjusts an overall length of tubing by combining a relatively small number of resonance tubes and valves, thereby changing the pitches of notes for scale adjustment. In this system, the operation of the first valve (in a trumpet, a valve closest to a mouthpiece) brings one resonance tube corresponding to a whole step (one tone) into communication, the operation of the second valve brings one resonance tube corresponding to a half step into communication, and the operation of the third valve brings one resonance tube corresponding to a whole and a half steps (one and a half tones) into communication. The communication of the resonance tubes results in an increase in the overall length of the tubing by the lengths of the resonance tubes due to the detouring of the tubing, thereby lowering the pitch of the notes. Therefore, by combining the aforesaid one step, a half step, and 1.5 steps, it is possible to produce notes that could not be produced without any valve. For example, in a trumpet without any valve, sol (G) would follow do (C) in a fundamental tone sequence (a fundamental tone sequence that is not a harmonic sequence), and none of re (D), mi (E), and fa (F) could be produced, and what makes it possible to produce these notes that could not be produced is the operation of the aforesaid combination of the valves. On the other hand, even with the valves, it is not always possible to produce correct notes by the valve operation. The lengths corresponding to the aforesaid one step, a half step, and 1.5 steps are determined by ratios to the overall length, and therefore, for example, the length corresponding to one step when the pitch is lowered by one step by the operation of only the first valve and the length corresponding to one step when the pitch is lowered by 1.5 steps (semitone+one tone) by the simultaneous operation of the second valve and the first valve are different from each other. That is, when seen from the first valve, the overall length is longer by a detour length due to the simultaneous operation of the second valve, compared with that when only the first valve is operated, and thus a length ratio for one step changes. This is a reason why the correct pitch note cannot be produced only with the valves. A difference in pitch caused by such a difference in the overall length is corrected by using tuning slides and lips of a player.
As for pitch correction by the simultaneous operation of a plurality of valves (for example, the simultaneous operation of the aforesaid first valve and second valve), an allowance is given by designing resonance tubes a little short in consideration of relative easiness of the downward pitch correction by the lips while the musical instrument is played and a difference between equal temperament and just temperament, and since only relatively small pitch correction is necessary when the second valve and the third valve are simultaneously operated, it has been practically sufficient if the resonance tube of the third valve is set to an appropriate length and only the downward pitch correction is made by the lips while the musical instrument is played.
However, in a high register where relatively high-order harmonics are produced, due to a narrow interval between two adjacent harmonics, reliability in sounding is lowered, and it is not easy either to make the downward pitch correction by the lips while the musical instrument is played. Therefore, for every register where a sufficiently large interval between harmonics can be ensured, it has been necessary to use a different musical instrument whose overall length is relatively short, thereby obtaining reliability in sounding in a high register. As described above, there has been a drawback that it is only in one of a high register and a low register that one kind of a musical instrument can obtain a degree of freedom in scale adjustment by using a relatively low-order harmonic range where an interval between harmonics is wide.
In the application where arbitrary musical compositions of music in general are played, this drawback is a great obstacle to a degree of freedom of musical performance. Concretely, there have been problems that part of notes is lacking during complicated scale adjustment in a register where an interval between harmonics is relatively narrow, an unnecessary note is produced during the scale adjustment of a high register, a note necessary for playing a musical composition cannot be produced due to the lack of a note in a low register, and the like.
One of methods to solve the problems is to use a four valve system and expand the lowest register further downward by 2.5 steps by coupling a bypass tube by a fourth valve. FIG. 20 is a tubing view showing a coupling route of a valve device and resonance tubes by this method. In FIG. 20, 23 denotes a first valve, 24 a second valve, 25 a third valve, 26 a fourth valve, 3 a mouthpiece, 5 a bell, 23v, 24v, and 25v resonance tubes, 7 a main tube, and 9 a bypass tube. However, nor is this method capable of improving reliability in the scale adjustment in a relatively high-order harmonic range because an interval between harmonics of the main tube which is a musical instrument main body is not changed, and great pitch correction is required also when the plural valves are simultaneously operated in the lowest register. A method in which bypass tubing of a fourth valve which lowers the register by 2.5 steps is made to communicate with correction tubes of a first, a second, and a third valve to automatically adjust the overall length of resonance tubes coupled to the first, second, and third valves according to the overall length of the bypass tubing as in an euphonium and a semidouble horn (FIG. 21) including an automatic pitch correction mechanism (correction pitch system) called a compensating system (see a patent document 1) requires that each of the correction tubes has a length substantially equal to a gap between a pair of coupled openings of the resonance tube, and thus this method is not applicable to a musical instrument whose resonance tubes are short and whose correction tubes accordingly become extremely short, such as a piccolo trumpet. Further, since the operation of the fourth valve results in a change in fundamental tonality unique to the musical instrument such as a C instrument and a B-flat instrument, fingering transposition is necessary. FIG. 21 is a tubing view by this method, and among the reference symbols shown in FIG. 20, the same reference symbols as those in FIGS. 1 and 2 represent the same members. Further, 33v, 34v, and 35v are the correction tubes. The automatic pitch correction mechanism proposed in the patent document 1 is a method for realizing such correction tubes with extremely short length, but since, in this method, the pitch correction when the first or second valve and the third or fourth valve are simultaneously operated is realized only in the alternative combinations, it is necessary that separate bypass tubes are provided and the bypass tubes communicate with the first or second valve in order for the third and fourth valves to have a pitch correction mechanism. Another method is to use a first, a second, and a third valve to each of which one set or two sets of resonance tubes different in length are independently coupled and switch to a bypass tube with different tonality by a fourth valve or the like, as in a full double horn and a full triple horn, but this further increases the weight of the musical instrument and also complicates fingering. FIG. 22 is a tubing view by this method, and among the reference symbols shown in FIG. 20, the same reference symbols as those in FIGS. 1 and 2 represent the same members. Further, 33v, 34v, and 35v denote resonance tubes. FIG. 23 is a tubing view of a piccolo trumpet according to an embodiment of the present invention which will be described later. The same reference symbols as those in FIGS. 1 and 2 are used in FIG. 23. This is attached for comparison.    Patent document 1: U.S. Pat. No. 5,052,261